The present invention relates generally to a method and system for insulating piping. More specifically, the present invention relates to a method and system for effectively insulating piping located in an exterior wall construction in a manner that protects the piping from freezing.
In the construction of residential and commercial structures a variety of piping systems are installed to allow delivery of water to various plumbing fixtures such as sinks and toilets. Further, hydronic piping is installed to circulate a fluid medium, which is some cases is simply water, to effect heat transfer in order to heat the space. Often, due to the design of the space or the location of the various fixtures and heating elements, such piping must be located adjacent or within the cavity of the exterior walls of the structure. The difficulty created in these instances is that during the winter the temperature outside the wall construction and often within the wall cavity itself fall below 32° F., the freezing point of the water contained within these piping systems. When examined closely, the heat profile of a typical wall construction can be seen to have temperatures approaching the interior ambient temperature at the inner surface of the drywall within the wall bay and temperatures approaching exterior cold temperatures at the inner surface of the exterior sheathing within the same wall bay. Turning to FIG. 1, a typical wall construction can be seen having a wall cavity 2 filled with R-19 insulation 4 sandwiched between drywall 6 on the interior surface and plywood 8 and shingles 10 on the exterior surface. Given an interior ambient temperature of 70° F. and an exterior condition of 5° F. with a 15 MPH wind the temperature of profile within the wall cavity 2 can be seen to reach as low as 9.93° F. at the interior surface of the exterior sheathing 8. While theoretically the piping can be protected from freezing provided that it is positioned on the interior half of the wall where temperature can he seen to be above 38° F., actual practice does not always meet the theoretical design requirements as will be discussed below.
Since it is well recognized that the space in the wall cavity of an exterior wall can often reach freezing temperatures, the International Plumbing Code and most state plumbing codes provide a basic requirement that domestic water pipes installed in outside walls shall be protected from freezing either by heat, insulation or both. One issue with such code provisions, however, is the fact that the code does not provide any specific direction as to how such protection against freezing should be provided. Further, while these code provisions apply to domestic water supplies, the difficulty arises in that the parallel code relating to heating systems has not provided any requirements regarding the protection of hydronic piping from freezing. This situation is further aggravated because the lack of direction a code level has translated directly into a lack of industry support for the installation of insulation on hydronic piping in exterior walls. As a result, there have been a large number of pipe failures directly tied to the freezing of the piping installed in exterior walls, wherein the pipe failure has caused extensive building damage. It has been reported that building damage due to frozen pipes is second in the United States only to hurricane damage.
Turning to FIG. 2, generally, in the prior art, installers simply provide for the installation of their piping into the wall cavity prior to the installation 4 of the building envelope. The installers then rely on the installer of the building insulation 4 to tuck the insulation material behind their piping thereby theoretically positioning the piping on the interior/warm side of the insulation 4 where it should be protected against freezing in most cases. While in theory such a practice should work, in most cases the actual installation does not comport with the theoretical ideal. For example, the installer of the insulation 4 may find it easier to install the insulation 4 over the top of the piping as shown at reference 12a leaving the piping 12a on the cold side of the insulation 4. Further, the installer may simply stop the insulation on either side of the piping as shown at reference 12b leaving a gap 14 that directly exposes the piping 12b to the cold side of the wall.
One insulation technique, known as “tenting” is one where batting insulation is draped over pipes that are run through unheated building cavities/attic spaces. The draped shape of the fiberglass (or similar) batting insulation is an attempt to prevent pipes installed in unheated building cavities from freezing. Part of the problem with this methodology is that the batting insulation that is used is not intended for this particular application. When draped over the pipe it becomes compressed, reducing its insulation value. Also, by creating a large building void space, this defeats the Energy Conservation Code, as well as Energy Star Guidelines, for building construction, and additionally creates large air spaces within building cavities that can lead to condensation, as well as mold growth. Also, freezing often occurs in pipes insulated in this manner due to inadvertent contact by building occupants, wind, or even animal contact which dislodges this insulation allowing cold draft contact.
A typical piping installation practice is for pipes to be placed on top of 2×6, 2×8, or 2×10 building construction members in an unheated attic when fire protection sprinkler systems are installed. When this piping arrangement cannot be modified and the possibility of passing this piping through these members by drilling a hole is not desirable for the installer, still, a methodology needs to be applied to protect this piping from freezing.
There are a number of different pipe insulation products that are currently available on the market today. Such insulation is generally configured as a pipe wrap in the form of jacketed fiberglass or a rubber material. These materials are installed fully around the exterior surface of the pipe thereby insulating the pipe. The problem that most people do not appreciated about the prior art insulation is that they are designed to prevent heat loss from the interior of the pipe to the exterior of the pipe. In other words they are intended to maintain the interior temperature of the fluid within the pipe. These insulation materials are not designed to address piping installed in locations for a long time that do not contain heated or moving water and this insulation is only intended to satisfy the requirements of the International Energy Conservation Code in reducing energy losses.
There is therefore a need for a method and system for insulating piping that is installed in attic locations servicing fixtures in the ceiling or spaces below. There is a further need for a method and system of insulating piping, such as wet sprinkler pipes in ceiling construction that reliably insures that the piping is protected from freezing by insuring that the piping is maintained as near to the ambient temperature of the interior of the structure as possible.